Abstract

Fusarium graminearum Schwabe (Fusarium head blight, FHB) and Puccinia triticina Eriks (leaf rust) are two major fungal pathogens posing a continuous threat to the wheat crop; consequently, identifying resistance genes from various sources is always of importance to wheat breeders. We identified tightly linked single nucleotide polymorphism (SNP) markers for the FHB resistance quantitative trait locus (QTL) Qfhs.pur-7EL and the leaf rust resistance locus Lr19 using genotyping-by-sequencing (GBS) in a wheat–tall wheatgrass introgression-derived recombinant inbred line (RIL) population. One thousand and seven hundred high-confidence SNPs were used to conduct the linkage and QTL analysis. Qfhs.pur-7EL was mapped to a 2.9 cM region containing four markers within a 43.6 cM segment of wheatgrass chromosome 7el2 that was translocated onto wheat chromosome 7DL. Lr19 from 7el1 was mapped to a 1.21 cM region containing two markers in the same area, in repulsion. Five lines were identified with the resistance-associated SNP alleles for Qfhs.pur-7EL and Lr19 in coupling. Two SNP markers in the Qfhs.pur-7EL region were converted into PCR-based KASP markers. Investigation of the genetic characteristics of the parental lines of this RIL population indicated that they are translocation lines in two different wheat cultivar genetic backgrounds instead of 7E–7D substitution lines in Thatcher wheat background, as previously reported in the literature.

Notes

Acknowledgments

This project was funded by USDA National Institute of Food and Agriculture competitive Grant Number 10-85117-20607 Award Number 58-3620-8-688 and USDA-ARS CRIS Number 3602-22000-018-00D-18. Mention of a commercial or proprietary product does not constitute endorsement or recommendation for its use by the USDA. The project was also funded by the Agronomy Department, Purdue University and the China Scholarship Council Fellowship. The authors wish to thank Shuangye Wu (Department of Pathology, Kansas State University) for assistance during GBS library construction. We appreciate Dr. Jessica Rutkoski (Plant Breeding and Genetics Department, Cornell University) who kindly provided advice for GBS analysis. We also thank Williams lab staff who assisted with DNA isolation.

Author contribution

X.X. and C.W. conceived the research and designed the experiments. H.O. and L.K. collected phenotypic data. H.O. constructed mapping populations. G.H. and X.X. performed QTL mapping. X.X. isolated DNA and performed statistical analyses. J.P. oversaw genotyping-by-sequencing. J.N. developed the KASP assay. C.W. directed the study.